WO2006129528A1

WO2006129528A1 - Front surface mirror

Info

Publication number: WO2006129528A1
Application number: PCT/JP2006/310293
Authority: WO
Inventors: Tadashi Onishi; Katsuhiko Kitagawa; Yasushi Ueno; Minoru Miyamoto
Original assignee: Central Glass Company, Limited
Priority date: 2005-06-02
Filing date: 2006-05-24
Publication date: 2006-12-07
Also published as: EP1873584A1; US20080253009A1; JP2006337770A; CN101180574A; CN101180574B

Abstract

A front surface mirror (3) for use in a rear projection television includes a glass substrate (11) on which a metal film (13) and metal oxide films (14, 15) are formed in this order. The surface of the glass substrate (11) is reformed by ion etching and the metal film (13) is an Al film. It is possible to provide a durable front surface mirror having a high reflectivity of the entire visible region when the reflection angle required by the rear projection television is large.

Description

Specification

Surface mirror

Technical field

TECHNICAL FIELD [0001] The present invention relates to a surface mirror used in a rear projection television in which a metal film and an oxide film are formed, and the rear force of a screen projects an image.

Background of the Invention

[0002] In recent years, there are devices that display large screens, such as rear projection televisions for large screen displays, flat panel displays, and projection televisions. Especially, rear projection televisions are considerably cheaper because they are inexpensive. The spread of is seen.

[0003] A rear projection is a projection screen such as a CRT that is projected onto a screen using an optical system. The rear projection reflects the display light using a mirror, lengthens the optical path with a small depth, and creates a large screen. I am trying to reflect it.

[0004] As a mirror used in a rear projection television, a so-called back mirror is formed by forming an Ag film on a glass substrate by a silver mirror reaction and forming a protective film on the Ag film. A surface mirror is used in which a metal film is formed, an oxide film is formed thereon, surface light of the oxide film is incident and reflected by the metal film.

[0005] The back mirror has a reflective film protected by a durable protective film, and is durable enough to be used in a bathroom or the like. Since the light is also reflected on the surface, there is a problem that a double image is generated in the display displayed on the screen, and there is a problem that the reflectance is low due to absorption of display light by the glass substrate.

[0006] The surface mirror is formed on the glass surface by physical vapor deposition or the like! Since the display light is directly incident and reflected on the metal film without passing through the glass, it reflects without the problem of a double image. The rate is also high.

[0007] For example, Patent Document 1 discloses a surface mirror in which a metal film containing Ag as a main component and added with Pd, Au, and Ru is formed by a sputtering method.

[0008] However, such a mirror is expensive because it uses a precious metal for use in a rear projection television used in general homes, and has a problem in durability against a high temperature / high humidity atmosphere. . Therefore, recently, a surface mirror using Al as a metal film has been used. For example, in Patent Document 2 as a surface mirror using A1, a thin film is deposited on a substrate in the order of Ti02, AIO, Al, and TiO.

twenty two

Reflectors have been proposed. The reflectivity of this surface mirror is 90% or less, and the hardness of the reflective film is difficult.

[0010] Patent Document 3 discloses a reflecting mirror in which a thin film is deposited on a substrate in the order of SiO, Al, Cr, and AlO.

2 2 3

Although it has been proposed, it cannot be used for rear projector TVs where the reflectance of this surface mirror is low.

[0011] Therefore, a commonly used surface mirror is formed on a glass substrate in the order of Al, SiO, and TiO.

2 2 A film-type reflective reflector is used, but this film configuration is inferior in wear resistance and cannot be wiped with a cloth if the surface becomes dirty.

[0012] As a solution to this defect, Patent Document 4 describes that Al, SiO, TiO, SixNy

twenty two

A surface mirror in which thin films are sequentially deposited has been proposed. The surface mirror with this film structure shows improved wear resistance, but the structure of the A1 film has not been improved, so sufficient hardness and durability have not been obtained.

[0013] Furthermore, as a recent demand from the factory, as shown in Fig. 1, there is a request to make the depth d of a projection television as thin as a plasma display panel (PDP) or a liquid crystal display (LCD). In order to solve this problem, it has been designed to increase the reflection angle between the light source and the surface mirror.

[0014] When the reflection angle of the A1 surface reflector is increased, the visible light reflectance decreases and the display brightness of the screen decreases, and the reflectance in the short wavelength region and the long wavelength region decreases, and the color tone is red. Alternatively, the problem arises that the color of the video of the video projection device 2 is not reproduced with a bias toward blue.

Patent Document 1: Japanese Patent Laid-Open No. 2001-226765

Patent Document 2: JP-A-6-51110

Patent Document 3: JP-A-6-130210

Patent Document 4: JP-A-6-130210

Summary of the Invention

[0015] A surface mirror with an A1 film formed on a glass substrate has a hardness that weakens the adhesion between the glass substrate and the A1 film. Since it does not have sufficient durability with respect to high temperature, moisture resistance, and salt water resistance, it has been difficult to use it as a reflector for rear projection televisions.

[0016] In addition, there is a drawback that the reflectance in the entire visible light range (400 to 700nm) is low when the reflection angle is large, and the reflection angle of the surface mirror is increased to reduce the depth of the rear projection TV. It was difficult to do.

An object of the present invention is to provide a surface mirror that solves such problems of durability and reflectance.

According to the present invention, in a surface mirror used in a rear projection television in which a metal film and a metal oxide film are formed in this order on a glass substrate, the surface of the glass substrate is modified by ion etching. And a surface mirror characterized in that the metal film is an A1 film. Brief Description of Drawings

FIG. 1 is a schematic cross-sectional view showing a film configuration of surface mirrors of Example 1 and Comparative Example 1 of the present invention.

FIG. 2 is a schematic sectional view showing a film configuration of a surface mirror of Example 2 of the present invention.

FIG. 3 is a schematic diagram showing a configuration of a rear projection television.

Detailed description

[0020] The surface mirror of the present invention provides a surface mirror having high durability and high reflectivity in the entire visible range when the reflection angle required for the rear projection television is large, and excellent in durability. Make it possible.

FIG. 3 is a schematic diagram showing a configuration of the rear projection television 1 in which the surface mirror of the present invention is used. The rear projection television 1 mainly includes a video projection device 2, a reflection mirror 3 that reflects an image projected from the video projection device 2, and a screen 4 that reflects an image reflected by the reflection mirror 3 in a casing 5. Etc. The video projection device 2 includes a display device such as a CRT and an optical system for projecting video.

[0022] In order to reduce the depth d of the rear projection television, it is desirable to make the incident angle α of the light beam of the display image near the center of the reflector to be 45 ± 25 degrees. It is desirable to have a large reflectance at an incident angle of 45 degrees.

[0023] The film configuration 10 of the surface mirror of the present invention includes a glass substrate, an A1 film 13, SiO 2 as shown in FIG. Film 14 and Nb O film 15 are deposited by physical vapor deposition in this order on a surface mirror or in Fig. 2.

twenty five

As shown, glass substrate 11, SiO film 12, A1 film 13, SiO film 14, Nb O film 15,

2 2 2 5

It is a surface mirror formed by a physical vapor deposition method in order.

[0024] On the glass substrate 11, a glass surface on which the A1 film 13 or the SiO film 12 is formed is formed.

2

Use what has been previously ion-etched.

[0025] As the glass substrate 11, a plate glass manufactured by a float process can be used.

Further, a glass called “high flatness glass” with less surface waviness or a polished glass with excellent flatness may be used.

[0026] The ion etching apparatus used in a manufacturing apparatus such as an LSI is used, an active gas having a pressure of 1 to 100 Pa is introduced in a vacuum state, and ions are introduced into the vacuum using a power supply apparatus such as a high frequency. The surface of the glass is thinly etched and modified by causing ions to collide with the glass at high speed. The etched glass surface has a very high activity, and the crystal structure of the A1 film formed on the surface of the glass can be arranged very precisely and regularly. As conditions for this treatment, it is preferable to use an ion etching voltage of 600 V or more, a treatment time of 3 seconds or more, and a mixed gas of oxygen and argon as the active gas.

As the physical vapor deposition method, a sputtering method, a vacuum vapor deposition method, an electron beam vapor deposition method or the like can be used. Of these, the sputtering method is recommended in consideration of easy film formation and good film adhesion.

[0028] The SiO film 12 on the glass surface is formed by directly stacking the A1 film 13 formed on the glass substrate on the glass substrate.

2

The film is formed in order to further improve the crystallinity of the A1 film rather than the film formed, and the film thickness is preferably 50 nm or less. Furthermore, there is no particular problem when the thickness is about lOOnm, but the crystallinity of A1 is almost constant even if it exceeds 50nm.

[0029] The A1 film 13 is a reflective film of a surface mirror. When the film thickness is 60 nm or more, a visible light reflectance of 90% or more can be obtained, and even if the thickness is increased at 60 nm or more, the reflectance is large. Therefore, a film thickness of 60 nm is sufficient. However, there is no particular problem even if the film thickness is larger.

[0030] The A1 film uses an aluminum target and is sputtered in an inert atmosphere such as Ar gas. Can be obtained.

[0031] As a measure for improving the corrosion resistance of A1, a film containing one or more metals selected from Mn, Mg, Si, and Nd of 5% by weight or less can be used as the A1 film. In order to contain Mn, Mg, Si, and Nd, it is obtained by forming a film in an inert atmosphere such as Ar gas using a target in which Mn, Mg, Si, and Nd are contained in an aluminum target.

[0032] However, it is preferable that Mn, Mg, Si, and Nd contained in the A1 film exceed 5% by weight because the crystallinity of A1 is impaired and the reflectance is lowered.

[0033] Note that Mn, Mg, Si, and Nd contained in the A1 film in order to improve the durability performance destroy the crystal structure of the Al film and lower the reflectivity, so the content should be suppressed as much as possible. Is preferred.

[0034] The SiO film 14 on the A1 film improves the adhesion between the A1 film 13 and the uppermost NbO film 15.

2 2 5

There is also an effect.

[0035] If the thickness of the SiO film 14 is 30 nm or more, the ratio of the A1 film directly deposited with the NbO film

2 2 5

A surface mirror with sufficient hardness, high temperature resistance and high humidity can be obtained. In addition, in order to obtain the effect of increasing the reflectivity due to the difference in refractive index with Nb205, the thickness of the SiO film 14 is 80 ± 40 nm.

2

It is preferable that

[0036] SiO film 14, using a Si target, an oxygen-containing cut of 50 to 100 weight ^_0/0 for Ar gas

2

It is obtained by sputtering in the atmosphere.

[0037] The Nb 2 O film 15 uses a niobium target, and is 50 to L00% oxygen by weight with respect to Ar gas.

twenty five

It is obtained by sputtering in a contained atmosphere, and is formed for the purpose of protecting the metal film and increasing reflection.

[0038] In order to use the surface mirror 13 for a rear projection television, the thickness of the NbO film 15 is reduced to 30.

twenty five

Sufficient high temperature resistance, high humidity and wear resistance can be obtained by setting it to more than nm. Also with SiO

To obtain the effect of increasing the reflectivity due to the difference in refractive index of

2 5 film 15 has a thickness of 60 people

The power to be 40mn S liked!

[0039] The surface mirror of the present invention is intended to be used as a reflection mirror of a rear projection television. In the process of manufacturing the surface mirror, the surface of the glass substrate is ion-etched using a plasma etching apparatus. The surface of the glass substrate is modified to a highly active surface, An Al film is formed on it.

[0040] The surface of the ion-etched glass substrate is very active. When an A1 film is formed on this ion-etched glass substrate, the crystal structure of the A1 film formed is ion-etched. As a result of the peak height of the X-ray diffraction, it is possible to form a dense A1 film that is much denser and regularly arranged than an A1 film deposited on an untreated glass substrate. Power is confirmed.

Example [0041] The results of measuring the peak height of the X-ray diffraction of Example 2 and Comparative Example 1 are shown in Table 2. The peak height of the X-ray diffraction of Examples 1 and 2 is the same as that of Comparative Example 1. The result is higher than the peak height of X-ray diffraction.

Table 1 shows the measurement results of the reflectance in the visible region of Example 2 and Comparative Example 1. As shown in Table 1, the A1 film formed on the ion-etched glass surface of Example 1 and Example 2 was subjected to the ion etching process of Comparative Example 1, and the reflection angle was larger than that of the A1 film. In the visible region (400 to 700 nm), which is not dependent and perceived by the human eye, a very high reflectance can be obtained.

[0043] Further, the A1 film formed on the ion-etched glass is much more excellent in hardness, high temperature resistance, moisture resistance, and salt water resistance than the A1 film not subjected to ion etching treatment.

[0044] Hereinafter, specific examples employing the sputtering method will be described in detail as an example of the present invention, but the present invention is not limited thereto.

[0045] Example 1

A surface mirror 3 having a film configuration shown in FIG. 1 was prepared using a float glass plate having a thickness of 3 mm and a size of 600 mm × 600 mm that had been washed and dried. All the films were formed by sputtering. First, the high-frequency power supply device is made by Shanaider (output 3k, 2A), and in the atmosphere of ArlOO (sccm), oxygen 70 (sccm) and vacuum pressure 0.1 lOpa, voltage is applied to generate reactive plasma by applying ΙΟΟΟν Under the condition, the angle between the ion etching apparatus and the glass was maintained at 45 degrees, and the glass was passed at a speed of about 1 (mmZmin) to modify the glass surface.

[0046] Next, using an advanced energy MF (medium frequency) power source, using a dual force sword with a Si target attached, argon 200 (sccm), oxygen 156 (sccm), and a vacuum degree of 0.18 (pa The SiO film 12 having a thickness of 30 nm was formed in an atmosphere of [0047] Next, a dual cathode in which an A1 target is mounted on the SiO film using the same power source.

2

A1 film 13 having a thickness of 80 nm was formed in an atmosphere of Ar300 (sccm) using a cathode.

[0048] Next, an SiO film 14 having a thickness of 80 nm is applied to the Si target using the same power source and force sword.

2

The film was formed in an atmosphere of Ar300 (sccm), oxygen 70 (sccm), and pressure 0.46 (pa).

Further, an Nb 2 O film was formed to 60 nm on the SiO film 14 using an Nb target. Completion

2 2 5

The membrane uses the same power supply, force sword, Nb target, Ar300 (sccm), oxygen 120

(sccm) and a pressure of 0.28 (pa).

[0050] Visible light reflectance of the obtained surface mirror is spectrophotometer (U-400 type at an incident angle of 8 degrees

As shown in Table 1, the reflectivity exceeding 90% was obtained over all wavelengths. In particular, the reflectivity at 400nm exceeded 90%, and it was a reflector capable of faithfully reproducing blue.

[0051] In addition, a reflectance measurement at 45 degrees was performed using an automatic absolute reflection measuring device V550 manufactured by JASCO Corporation, and the results shown in Table 1 were obtained.

[0052] As shown in Table 1, it was confirmed that a reflectivity of 90.0% or higher was obtained over all wavelengths even at 45 ° incidence, and the reflectivity hardly changed depending on the incident angle.

[0053] Durability of the reflector of Example 1

Adhesiveness: Adhesive tape (Scotch Mending Tape 3M # 800) is applied to the film, then peeled off, and the film formed per 45mmφ is peeled off and the number of pinholes (number) generated in the film is determined. Observed and measured with a microscope.

As a result, it was confirmed that there was no peeling of the film and the number of pinholes was 0, and there was no problem in the adhesion of the film to the plate glass.

[0055] Hardness: A weight of 450 gZcm ² was placed on the film surface with 6 layers of flannel, and this was slid 500 times at a stroke distance of 100 mm to change the transmittance of the sliding part. It was measured. The transmittance was 0% before and after the test, and therefore the change in transmittance due to the test was also 0%, confirming that there was no problem with the film hardness.

[0056] Humidity resistance: When left in an atmosphere of 50 ° C and 95% RH (relative humidity) for 24 hours, a high-temperature and high-humidity test was performed, and the appearance change of cloudiness and other films was observed. No change in appearance was observed, and it was confirmed that high temperature resistance and high humidity were sufficient. [0057] High temperature resistance: When left in an atmosphere at 70 ° C for 24 hours, a high temperature test was conducted! The appearance of cloudiness and other films were observed. It was confirmed that the high temperature resistance was sufficient.

[0058] Resistance to high and low temperatures: Cycles after standing in an atmosphere of 40 ° C and 30% RH for 24 hours, leaving it to stand naturally for 1 hour, and leaving it in an atmosphere of –10 ° C for 24 hours and then leaving it naturally for 1 hour A high / low temperature cycle test was conducted with two cycles per cycle, and cloudy and other changes in the appearance of the film were observed. It was confirmed that.

[0059] Salt water resistance performance: A salt spray test was conducted in a 35 ° C atmosphere in a 5% salt water atmosphere for 240 hours, and the appearance of fogging and other films was observed. No change was observed and it was confirmed that the salt water resistance was sufficient. This salt spray test is the most severe test for surface mirrors, and it is usually said that there is no problem if it passes 24 hours, and Example 1 does not cause deterioration for 10 times this period. It can be said that the durability is very good.

[0060] Example 2

A reflector having a film configuration 10 shown in FIG. 2 was produced. Example 1 is between the glass substrate and the A1 film.

A surface mirror of Example 2 was fabricated under exactly the same conditions except that no Si02 film was formed.

[0061] The visible light reflectance (incidence angle: 8 degrees) of the surface mirror of Example 2 was determined by measuring the reflectance according to visible light wavelength with a spectrophotometer (U-400 type, manufactured by Hitachi, Ltd.). Over 90% reflectivity was obtained.

[0062] In addition, the automatic absolute reflectance measuring device V550 manufactured by JASCO Corporation showed a reflectance of 45 degrees as a result of the reflection. As a result, even at 45 degrees shown in Table 1, a reflectance of 88.0% or more was observed over all wavelengths. Obtained.

[0063] Compared with Example 1, the reflectivity was 0.3 to 1.5% smaller, indicating a reflection characteristic with no significant difference.

[0064] As a result of performing the same durability test as that of Example 1 on the surface mirror of Example 2, it was confirmed that the surface mirror was sufficiently durable as in Example 1.

[0065] Comparative Example 1 Except that the glass substrate was not subjected to ion etching, the same film formation as in Example 1 was performed to produce a surface mirror. The same reflectance measurement and durability test as in Example 1 were performed.

[0066] The reflectance measurement results are as shown in Table 1. Compared with Example 1 and Example 2, the reflectance is lower when the reflectance is lower or further angled at short wavelengths and long wavelengths. ing.

[0067] The same durability test as in Example 1 was performed on the surface mirror of Comparative Example 1. The adhesion, moisture resistance, high temperature resistance, and high / low temperature resistance were the same as in Example 1, but in the hardness test, the transmittance before and after the test showed 0%. In the salt water resistance test, scratches occurred, white turbidity was observed in the periphery after 7 days, white cloudiness was observed on the 10th day, and the reflectance was decreased. The result was inferior in comparison.

[table 1]

(Unit <½)

[Table 2] Diffraction angle (2 diffraction intensities

(Degree) (CPS)

38.472 29.1

Example 1

44.738 9.5

38.472 26.0

Example 2

44.738 7.0

38.472 12.0

Comparative Example 1

44.738 1.0

Claims

The scope of the claims

[1] Rear projection in which a metal film and a metal oxide film are formed in this order on a glass substrate In a surface mirror used in a television, the surface force of the glass substrate is modified by S ion etching, and the metal film Is a surface mirror characterized by being an A1 film.

[2] The metal oxide film is characterized by sequentially laminating a SiO film and a NbO film on the A1 film.

2 2 5

The surface mirror according to claim 1.

[3] The SiO film is formed between the glass substrate and the A1 film, or 1

2

2. The surface mirror according to 2.

[4] The A1 film according to any one of claims 1 to 3, wherein the A1 film contains one or more metals selected from Mn, Mg, Si, and Nd in an amount of 5% by weight or less with respect to A1. The surface mirror described in 1.